1. Field of the Invention
The present invention relates to novel, inexpensive, lightweight, non-biodegradable forms for simple assembly in spaced relation to produce concrete-receiving walled channels for the pouring of concrete footings to support walls of buildings such as homes and other structures.
2. State of the Art
Wood planking has been used over the years, and is still used nearly exclusively, to produce retaining forms for the installation of concrete wall footings. Wood planks have the advantage that they can be nailed to one another to provide lengths corresponding to the desired inside and outside length of the footing being formed, and can be nailed to each other at an angle, such as 90xc2x0, to produce inner and outer corners of the form to produce the necessary corners of the footing form assembly around the periphery of the structure being built.
However, the use of wood planking for footing forms has certain disadvantages. Wooden footing forms are biodegradable and therefore building codes require that they be removed after the concrete footings are poured and cured. Wood planks are also relatively heavy, and porous and water-absorbing so that they absorb and bond to the concrete composition and become heavier and difficult to remove from the cured footing, and difficult to clean for reuse.
It has been proposed to use non-biodegradable materials to produce footing form assemblies, which can be left in place adjacent the formed wall-supporting footing to provide water-drain conduits and/or radon-escape conduits around the periphery of the footing. Such structures generally are hollow, flow-permitting enclosures which admit and conduct water and/or radon gas to a desired outlet, and which are not nailed in place. Reference is made to U.S. Pat. Nos. 5,224,799; 5,399,050; 5,474,400; 5,475,950 and 5,466,092 for their disclosures of such footing forms.
Reference is also made to U.S. Pat. Nos. 3,613,323 and 5,406,758 for their disclosures of drain tile forms for forming footings with integral water drainage conduits.
The present invention provides novel footing form members which are rigid, lightweight, non-biodegradable and water-repellant for ease of installation assembly to outline the length and corners of a desired foundation footing, and permit simple removal and cleaning, if desired, for reuse.
The present footing form members are elongate plastic planks, preferably about 8 to 12 feet in length, about 7 to 10 inches wide to correspond to the height of the desired footing, and about 1.5 to 2 inches in thickness or more, to provide the necessary rigidity while permitting the planks to be abutted lengthwise and staked or nailed to provide the desired length of the form and to be abutted perpendicularly and staked or nailed to form corners of the peripheral footing form assembly.
The present plastic planks are extruded from water-resistant thermoplastic molding composition such as high impact strength polyethylene, polystyrene, acrylonitrile-butadiene-styrene (ABS) or similar compositions, in a hollow configuration having spaced inner and outer walls connected by reinforcing ribs. The spaced walls are relatively thin and may be formed of closed-cell thermoplastic polymer foam, i.e., between about 0.03 and 0.30 inch thick. The planks are nailable to each other or to supporting stakes, or frictionally-engage supporting stakes.
According to a first embodiment, the present hollow plastic planks have a bracket-shaped or C-shaped cross section with upper and lower horizontal flanges provided with aligned stake-receiving holes for receiving stakes for supporting the width of the planks in vertical position.
According to another embodiment the present planks are tubular in cross-section and hollow or filled with closed-cell thermoplastic polymer foam, and are provided with linear-spaced integral reinforcements through the width thereof to reinforce the plastic planks for nailing in vertical position along the ground to form assemblies which outline the width and height of the desired peripheral concrete footing to be poured.